Industry Standard Mailbox Sizes for email

Gary McFadden wrote an interesting article discussing exchange 2010 and it's new features/functions.  I stumble upon while searching for "industry standard mailbox sizes".  I know the first answer is like a lot of things in IT "It depends".  For a SMB I'm thinking 1GB for exec's 500 meg for mid management and ..??  what for everyone else.  Actually, is 500 meg enough?  perhaps 1gig, 3/4 gig, and 1/2 gig for the tiers?
I'm hoping someone out there will reply with what they think is standard and what size company they are used to.
thanks!

ISA and sharepoint gridviews

Rather then bore you with all the details of hours spent to find this little gem.. I'll just say
"Link translation".
If you turn off link translation for the rule that publishes your sharepoint site in ISA, Gridviews (aka. dataviews of datagrid views) will work like you were hitting the IIS server and not looping through ISA. Now a little more about this scenario. The sharepoint site was up and running just fine and dandy with it's new ISA reverse proxy when came the calling.. the "gridviews are locking up". Turning off link translation either just for that firewall rule, or if you like.. turn off the "add-in" link translation filer all together (first way does one site, the second turns off the feature on the ISA server and all the sites it publishes).
I hope that saves one of you hours of work.